Transcript Reading a Ruler

Reading a Ruler
Escambia County School Board
Office of Career and Technical Education
0
1
The distance is representing a full inch.
The full inch is divided into two sections.
The number of sections determines the denominator.
Notice the line height.
0
1
1
2
Each half inch section is divided into two sections.
Notice the line height. It’s getting smaller.
Remember the number of sections determines the denominator.
0 What will the denominator be for the new lines?
1
2
1
Each half inch section is divided into two sections.
Notice the line height. It’s getting smaller.
0
The denominator is 4 because of the 4 sections
created by the new lines.
1
4
1
2
3
4
1
Each forth inch section is divided into two sections.
Notice the line height. It’s getting smaller.
0
The denominator is 8 because of the 8 sections
created by the new lines.
1
8
1
4
1
2
3
5
8
8
3
4
1
7
8
Each eighth inch section is divided into two sections.
Notice the line height. It’s getting smaller.
The denominator is 16 because of the 16 sections
created by the new lines.
0
1
2
1
4
1
8
1
16
3
16
5
16
3
5
8
8
7
16
9
16
3
4
1
7
8
11
16
13
16
15
16
You now know all the fractions on a common school
ruler.
But how can you tell the fractions just by look at the
line heights?
0
1
1
2
1
4
1
8
1
16
3
16
5
16
3
5
8
8
7
16
9
16
3
4
7
8
11
16
13
16
15
16
PAY CLOSE ATTENTION NOW
0
You can tell what the fraction is for each line by
covering the lines up.
1
PAY CLOSE ATTENTION NOW
Cover the lines up.
0
1
PAY CLOSE ATTENTION NOW
NOW expose the first set of lines.
HOW many sections are created?
0
1
2 sections. That tells me the denominator
0
1
2
Count by odd numbers for the numerator.
Remember the 2 sections. That tells me the
denominator.
0
1
1
2
Expose the next set of lines.
The number of sections created tells me the denominator.
0
1
1
2
4
4
Count by odd numbers for the numerators.
0
1
1
4
1
2
3
4
Expose the next set of lines.
The number of sections created tells me the denominator.
0
1
1
2
1
4
8
8
3
4
8
8
Count by odd numbers for the numerators.
0
1
1
8
1
4
1
2
3
8
5
8
3
4
7
8
Expose the next set of lines.
The number of sections created tells me the denominator.
0
1
1
4
1
8
16
1
2
16
3
8
16
3
4
5
8
16
16
16
7
8
16
16
Count by odd numbers for the numerators.
0
1
1
4
1
8
1
16
1
2
3
16
3
8
5
16
3
4
5
8
7
16
9
16
11
16
7
8
13
16
15
16
You try it.
Expose the first set of lines.
0
1
What is the denominator?
0
1
The denominator is 2.
Now what is the numerator?
0
1
2
The numerator is 1. It’s the first odd number.
Now try the next set of lines.
0
1
1
2
The denominator will be 4.
The numerators will be 1 and 3. Count by odd numbers.
0
1
1
2
The denominator will be 4.
The numerators will be 1 and 3. Count by odd numbers.
Now expose the next set of lines.
0
1
1
4
1
2
3
4
What will denominator be?
The numerators will be? Remember, count by odd numbers.
0
1
1
4
1
2
3
4
The denominator will be 8.
And the numerators will be 1,3,5 and 7.
Now expose the last set of lines.
0
1
1
2
1
1
8
4
3
8
5
8
3
4
7
8
What will denominator be?
The numerators will be? Remember, count by odd numbers.
0
1
1
2
1
1
8
4
3
8
5
8
3
4
7
8
The denominator will be 16?
The numerators will be? 1,3,5,7,9,11,13 and 15. Remember,
you count by odd numbers.
0
1
1
2
1
4
1
8
1
16
3
16
3
8
5
16
3
4
5
8
7
16
9
16
11
16
7
8
13
16
15
16
Why do we count by odd number?
Remember math class and reducing fractions.
We only have odd number in the numerators because an
even number could be reduced.
0
1
1
2
1
4
1
8
1
16
3
16
3
8
5
16
3
4
5
8
7
16
9
16
11
16
7
8
13
16
15
16
All the red fractions can be reduced. Do you see any patterns?
0
1
1
8
1
4
1
2
3
8
5
8
3
4
7
8
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
16 16 16 16 16 16 16 16 16 16 16 16 16 16 16
Take the Measuring Test
Level 1